4 Apr
2011
4 Apr
'11
6:01 p.m.
On 4/4/11 8:25 AM, "Steven Hirsch" <snhirsch at gmail.com> wrote:
On Mon, 4 Apr 2011, Geoffrey Reed wrote:
When I'm desoldering, I put the edge of the hole against the leg for about 1
to 2 seconds then hit the suction. If it doesn't come clean, I resolder and
give it another go. One thing I do is once I start the suction I press the
leg against the other edge of the hole with the nozzle, that way I know I
get all the solder out.
Something you may want to consider if the desoldering isn't going well for
you, there are a few low temp alloys made for desoldering, you resolder the
pins with the alloy and then can generally completely clean it out using
braid or a desolder tool.
I have managed to lift traces with my hot air reflow tool, but I chalk that
up to not having used one in > 10 years and being WAY out of practice... I
am starting to get pretty good at listing surface mount IC's though :)
Perhaps I am just weird, but I rarely damage
circuit boards or components
when de-soldering. I have a Hakko 808 de-soldering gun.
Anecdotally, I suspect the Hakko unit has substantially better suction
than my aging OK or the BlackJack.
The biggest things I have learned from
de-soldering are:
Add fresh solder where you are able to, I have notices as solder ages and
oxidizes it gets to be a nightmare to melt. Also fresh Flux can help some
times.
Keep your de-soldering nozzle cleaned, I use the sponge on my Hakko 936 ESD
safe temp controlled solder station.
Once you hear the de-soldering gun start to labor, you need to check for
obstructions, and make sure your receptacle is NOT full of solder and the
flux filter is not plugged up.
I'm religous about all of that.
I am at the point on it where 95% of the time I
can get IC sockets out of pc
boards without damaging them. And have yet to *knock on wood* lift a trace
on a board I was repairing, including the ATARI XF551 single sided boards
where the traces are held on with good wishes.
<sigh> That was my hope. I add solder, clean the tip, hold it in place
until things are heated through and pull the trigger. It burrappps away
and just about nothing happens. Except thermal shock to the board,
tearing of adjacent traces, etc.
Since most of the devices I work on use 60/40 leaded solder, what is the
recommended tip temperature? How long do you leave it in place on, e.g. a
through-hold IC lead before triggering the vacuum?
May be that both these units are substandard. Getting desperate enough
that the Hakko is starting look like a good investment.